1. Field of the Invention
This invention relates to an emulsion production apparatus. More specifically, the present invention relates to an apparatus for producing emulsion fuel with high stability for use as low-pollution fuel.
2. Description of the Related Art
Emulsion fuel, in which water is added to a fuel oil such as light oil, heavy oil and heavy gravity oil to bee stirred and water is dispersed in the fuel oil, has been well known. Here, the heavy gravity oil is oil which is poor in flow-ability in room temperatures and does not flow without being heated at high temperatures, and includes the following oil in which an ingredient having a boiling point of 340° C. or more at ordinary pressure is preferably contained 90 wt. % or more. The oil includes a king of petroleum asphalt and its oil mixtures, various types of resultant products of petroleum asphalt, their intermediate products, residual dross and mixtures thereof, a high fluid-point oil which does not flow at room temperatures or a crude oil, petroleum tar pitch and its oil mixtures, a kind of bitumen, natural asphalt, orinoco tar, tar, a resultant-product oil.
When the emulsion fuel is sprayed into a high temperature field, the water in fuel liquid droplets is immediately boiled, the fuel liquid droplets are atomized (micro explosion), thereby burning at high speed and with high efficiency is actualized, and occurrences of CO and smoke may be suppressed. Since flame temperatures are decreased by the evaporation of water and NOx in an exhaust gas is effectively reduced, the emulsion fuel has been known as the low-pollution fuel.
In producing the emulsion fuel, the quality of performance of a mixer strongly affects on burning performance and long-term stability of the produced emulsion fuel. As regards the conventional mixer, specifically, an in-line type mixer, a static mixer, a high-pressure homogenizer, etc., have been utilized.
In the case of the static mixer, a fin column of which the twisting directions alternately invert is inserted so that fluids advance into a pipe while alternately rotating.
In contrast, in the case of the homogenizer, it blows out the fluids from fine nozzles under high pressure from several hundred to several thousand atmospheric pressure, and accelerates a fine mixture by strong shearing force caused by the blowing.
Furthermore, a technique is disclosed, with which the emulsion fuel is collided with each other by pressing it out from a pump or by jet blowing it out from the nozzles at high speed, agitated with a rotor, also allowed to pass through a magnetic field applying apparatus to tear off each molecule cluster of micelle particles, and with which accelerates mixture and diffusion of the micelle particles by electromotive power, and reduces particle diameters. For instance, refer to Jpn. Pat. Appln. KOKAI Publication No. 2004-161943.
With respect to the heavy gravity oil such as asphalt and oil sand, a production method for producing the emulsion fuel is disclosed, which includes steps of pre-mixing each row material, which is supplied from a heavy gravity oil tank, an emulsifying agent tank and a water tank which are kept at predetermined temperatures by a fixed quantity pump by a static mixer, agitating the row material by means of a high-shearing mixer (here, a pipe-line homo-mixer made by TOKUSHU KIKA KOGYOU CO., LTD. is used) and transferring the emulsion fuel to a heavy gravity oil emulsion fuel tank through a temperature regulator, for example, in Jpn. Pat. Appln. KOKAI Publication No. 8-209157.
Generally, the emulsion fuel itself is not stable with time as emulsion fuel. That is, the emulsion fuel in which only water is converted into fine particles to disperse into oil is agglutinated and separated into two phases of the oil in an upper layer and the water in a lower layer in due course of time. It is impossible for such fuel in which the oil and the water are separated into two phases to be used as fuel. Therefore, it is necessary to secure the dispersion stability with time in transportation and storage. To secure the dispersion stability with time, conventionally, a method is proposed for making a diameter of the dispersed water particles fine or adding a stabilization agent. Refer, for example, to Jpn. Pat. Appln. KOKAI Publication No. 2-105890.
However, as regards the production of the emulsion fuel, in the case of the use of the foregoing static mixer, a sufficient fine mixture may not be achieved.
There is such a problem that the high-pressure homogenizer produces a small production quantity although the energy quantity to be consumed in producing the emulsion fuel is large, and the cost of the production apparatus increases.
Regarding the heavy gravity oil, the high shearing mixer is used as a means for dispersing the water into a fuel oil. However, a big-sized agitation blade becomes required to sufficiently disperse the water into the fuel oil if only an agitation operation caused by high-speed rotation of the agitation blade of the high shearing mixer is used, wherein the load on the mixer is made heavy, the replacement frequency of the agitation blade is increased, and electricity expenses are high.
When the emulsion production apparatus agitates in a single rotating stream by the agitation blade, it is hard to evenly mix the oil with the water in a short time and hard to precisely control the moisture content of the emulsion fuel, since rough particle liquid droplets with large mass are adhere to the inner wall of an agitation vessel by the centrifugal force. Especially, in the case of a high-viscosity fuel oil such as C heavy oil, it is hard to evenly mix it with the water in a short time.
Further, to agitate and mix the high-viscosity fuel such as the C heavy oil in the single rotating stream by the agitation blade, it is necessary to heat the fuel oil at around 140° C. to enhance the liquidity, and thus it is impossible to use low-quality fuel without requiring expenses, since energy, time and a facility for heating are needed.
Although it is necessary to add an emulsion agent of around several percent to the fuel oil, the mixture of the emulsion agent of around several percent gives rise to a problem to raises a price of the emulsion fuel and to make the emulsion agent adversely affects the burning of the emulsion fuel.
The present invention is made by taking such a situation into account, and an object of the present invention is to provide an emulsion production apparatus capable of producing the emulsion fuel with high performance and stability.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.